Varnish: How often is DNS name lookup done when specified in ACL?

Question

I specified a dyndns domain name in a ACL of Varnish, so only IPs of this domain name should be allowed.

This is working fine until my IP changed. Then I get a forbidden error until I restart varnish.

How often does varnish refresh the DNS lookup?

I know it might be slow to do such lookups, but this is anyways not a production site.

Answer 1

With few lines of scripting you will be able to do that.

You need to setup a shell script which its purpose will be to periodically dig +short your domain name and if IP has changed, will reload varnish.

Answer 2

On parsing the config, varnish always does a lookup. Problem: Varnish reload looses the cache.

Solution: Using the varnish console load the new config under a different name, remove the old one.